Lo Shu grid

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine context beyond that: it explains the Indian-practice convention of injecting moolank/bhagyank into the grid and that this injection is optional, plus what the response enumerates. It does not spell out the cost/credit implication inline, which is minor given endpoint metadata is supplied.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core concept and then the output inventory; every clause (planes, arrows, lines, toggles) carries information rather than filler. It is a single dense run-on sentence, which costs a little readability but wastes no words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the definition needn't describe return values, and it still outlines the returned components. Required input (date) and optional toggles are covered, so an agent could call this correctly; only guidance about when to prefer Lo Shu over other numerology charts is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67% and already documents addDriver/addConductor with defaults; the description nonetheless adds domain meaning by naming them driver (moolank) and conductor (bhagyank) and framing them as an Indian-practice addition that can be switched off. The date parameter's meaning (birth date whose digits fill the square) is explained even though its format lives in the schema pattern.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('The 3x3 Lo Shu square ... filled from the digits of a birth date') and enumerates the concrete contents produced: present/missing/repeated numbers, the six planes, arrows, and full/empty lines. This is clearly distinguishable from the Chaldean and Kabbalistic numerology siblings without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the highly specific subject matter (Lo Shu grid requires a birth date), and the description notes driver/conductor 'each can be switched off', which hints at the toggle behaviour. However, there is no explicit when-to-use guidance, no exclusions, and no routing against the many alternate numerology systems listed as siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.